[13p-2L-1~11] 9.1 Dielectrics, ferroelectrics

[13p-2L-1] Temperature dependence of electric-field-induced strain properties of (Bi_1/2Na_1/2)TiO₃–BaTiO₃ single crystals

〇Kohei Makisumi¹, Motohiro Ogino¹, Yuuki Kitanaka¹, Yuji Noguchi¹, Masaru Miyayama¹, Shuki Torii², Takashi Kamiyama² (1.The Univ. of Tokyo, 2.KEK.)

Keywords:ferroelectrics,phase transition,strain

0.965(Bi_1/2Na_1/2)TiO₃–0.035 BaTiO₃ single crystal was grown by a top-seeded solution growth(TSSG) method at a high oxygen partial pressure of 0.9 MPa. Electric-field-induced strain of the crystal with monoclinic (Cc) structure was investigated at various temperature. It was showed that the strain was linear at 120 ^oC and that the S_max/E_max of the crystal was 756 pm/V with a large strain jump at 130 ^oC. It was revealed that between 120−130 ^oC, there is a phase transition between Cc phase and P4bm phase, and above 130^oC, the strain jump was due to electric-field-induced phase transition between P4bm phase and P4mm phase. The temperature–electric-field phase diagram composed of Cc, P4bm and P4mm phases was proposed in this composition.